There is known a projection display device having a tilt foot mechanism of adjusting a projection angle. The projection angle is an angle of the optical axis of light projected from the projection display device to a horizontal surface.
The general tilt foot mechanism has a rod-shaped foot disposed on the front side of the projection display device and a locking mechanism for adjusting the length of the foot. The foot is inserted into a case bottom surface to be movable in an axial direction. The locking mechanism is rotatably attached to the case, and engaged with the foot to fix the foot. In other words, the length of a portion of the foot projected from the case bottom surface (projection length) can be adjusted.
Accordingly, when the projection length of the foot is large, the front side of the case is high. When the projection length of the foot is small, the front side of the case is low. In other words, when the projection length of the foot is changed, the tilting (tilt angle) of the case to the horizontal surface changes, and the projection angle changes. Thus, the projection angle can be adjusted by adjusting the projection length of the foot.
Patent Literature 1 describes an example of such a tilt foot mechanism. The tilt foot mechanism described in Patent Literature 1 includes a case member, a foot member inserted into the case member, an operation lever rotatably attached to the case member, a cap member for covering the upper opening of the case member, and a coil spring disposed between the cap member and the operation lever. The operation lever is rotatable between a first position where the lever is engaged with the foot member and a second position where engagement with the foot member is released. The coil spring always presses the lever so that the operation lever can be maintained at the first position. Thus, when the operation lever at the first position is rotated against the pressing of the coil spring, the engagement between the operation lever and the foot member is released, enabling adjustment of the projection length of the foot member.